Solve with numerical values from table.

An R$-134$A cascade refrigeration cycle operates with evaporator

temperature of $-40F$ and condenser pressure of $300$ psia $.$ The

compressor efficiency of both units is $0\mathrm{.}90.$ Assume the heat exchanger

between the upper and lower units operates at $40$ psia for upper unit

and $50$ psia for the lower unit.

a$.$ Draw and label a T$-$s diagram for this system.

b$.$ If this cycle must deliver $10$ tons of refrigeration, determine the

mass flow rates.

c$.$ Calculate the COP of the cycle assuming $10$ tons of refrigeration.

d$.$ Calculate the COP of a simple refrigeration cycle with a

compressor efficiency of $0\mathrm{.}9$ operating between the same

evaporator temperature and condenser pressure as the cascade

cycle.